Why are Salmon in Trouble?
Salmon are one of the premier native fish of the Pacific Northwest. They evolved with the region over geologic time. For thousands of years, they have been central to the culture, religion and livelihood of the region’s native people.
The decline of the Columbia River’s once-numerous salmon and steelhead runs is well documented. Human activities that degrade or diminish habitat are the primary cause of the decline of these fish. Federal agencies have a fundamental responsibility under the Endangered Species Act to prevent extinction and foster recovery of listed species.
Why are salmon in trouble?
Over-fishing
One hundred years ago the major threat to salmon was commercial fishing, and as early as the beginning of the 20th century people began to notice the runs were declining. Gill nets, seines and fish wheels all decimated salmon populations. While many mass-catch fishing methods were outlawed over time, salmon runs continued to decline as over-fishing was replaced by other hurdles for salmon such as dams, habitat destruction and even early hatchery practices.
Dams
Dams are probably the most publicized problem for salmon. Dams can block or impede migration and have created deep pools of water that in some cases have inundated important spawning habitat or blocked access to it. Dams also change the character of rivers, creating slow-moving, warm water pools that are ideal for predators of salmon. Low water velocities in large reservoirs also can delay salmon migration and expose fish to high water temperatures and disease.
Many things have been done to reduce the impacts of dams on fish. Fish passage facilities and fish ladders have been developed to help juvenile and adult fish migrate around many dams. Spilling water at dams over the spillway is an effective means of safely passing juvenile fish downstream because it avoids sending the fish through turbines. Water releases from upstream storage reservoirs have been used to increase water velocities and to reduce water temperatures in order to improve migration conditions through reservoirs. Juvenile fish also are collected and transported downstream in barges and trucks.
Fish Ladder at Columbia River damMany other solutions to the problems that dams pose have been suggested – including removing them. A number of small dams in the Pacific Northwest that block salmon migration have been removed or are being considered for removal. The removal of larger hydroelectric dams, such as those on the lower Snake River, has been very controversial and currently is not being considered as an option.
Poor Habitat
A salmon’s world covers thousands of miles. During its four to five-year life span, an individual salmon can migrate from inland mountain streams to the Pacific Ocean, using many different habitats in between.
Common threats in streams include pollution, the destruction of stream-side plants and the lack of clean, cold water.
Pollution comes in many forms. Erosion from logging and development washes into streams, covering salmon eggs and suffocating them. Runoff from city streets, agricultural land and neighborhoods introduces harmful chemicals into streams, injuring or killing salmon and other stream inhabitants in the food chain.
Riparian (stream-side) plants shade the water, keeping the stream cooler (salmonids prefer cold water). Plants provide wood and roots that shelter young fish and provide resting places for them. Plants also filter pollution and hold soil in place to minimize erosion.
Rivers may become slow and warm when water is withdrawn for farming and other uses, making them unhealthy for salmon. Sometimes salmon and other fish, such as bull trout, are stranded in small pools when sections of a river dry up from too many withdrawals.
stream bank damage with gravel hillsThe biggest threat to salmon today is the loss and degradation of habitat. The problem is compounded by the fact that each life stage of a salmon, from egg to adult, requires a specific habitat. There are issues and concerns along each life stage and in each habitat, making salmon recovery complex, far-reaching and contentious.
Hatchery practices
Salmon hatcheries were originally built to replace runs of salmon whose natural habitats were either lost behind impassable dams or disturbed to the point that they could not sustain natural production. Hatchery programs were designed to replace lost fisheries. As a result, hatcheries produced large numbers of juvenile salmon for release without fully understanding how they would compete with wild salmon for food and habitat.
As hatchery and wild fish stocks mixed together, larger hatchery populations masked declines in wild fish populations, resulting in delayed changes in management practices to protect wild fish.
Modern hatchery and fishery management programs recognize these problems and are designed to minimize these impacts. Today, hatchery roles and responsibilities have broadened beyond producing fish for sport, tribal and commercial harvest to ensuring that their programs are compatible with conserving wild and naturally spawning fish. We are creating new roles for hatcheries that include conserving and protecting genetic reserves of unique stocks of fish, developing hatchery stocks that more closely imitate wild stocks in their genetics and behavior and using appropriate stocks in rebuilding runs of salmon to spawn in the wild.
Why you should care
The problems and solutions belong to everyone.
Salmon are not only a profound component of the Northwest’s economy and identity; they have been a spiritual and cultural center of Northwest Native American tribes for thousands of years. Salmon decline has been slow but sure and is the result of many factors. The solution will be equally slow and complex and will not come from simple actions.
The possibility that wild salmon may become extinct indicates that our waterways are in such bad shape they can no longer support a species that has been in our rivers and streams for eons and once numbered in the millions. And ultimately, human health also is dependent on healthy rivers.
Once a wild run is lost it will not return. Extinction is forever.
Topic: salmon